Relationship Between Sonographic Foetal Thymus Transverse Diameter and Histological Chorioamnionitis in Patients with Preterm Rupture of Membranes in Ibadan, Nigeria.

Abstract

INTRODUCTION:

One of the major challenges faced by the clinicians in the management of preterm rupture of the membranes (PROM) is to correctly identify when a significant chorioamnionitis is evolving to decide the appropriate time for delivery of the fetus. A promising diagnostic tool to serve as a surrogate marker for predicting the occurrence of subclinical chorioamnionitis is the use of sonographic fetal transverse thymus diameter (FTTD). The objective of this study was to determine the relationship between sonographic FTTD and histological chorioamnionitis in patients with PROM.

METHODOLOGY:

 This hospital based prospective cohort study was conducted among consenting pregnant women who presented with PROM between gestational ages of 28 to 34 weeks at the University College Hospital, Ibadan, Nigeria over an 8-month period. Sonographic measurement of fetal thymus transverse diameter (FTTD) was performed on all fetuses at admission. After delivery, the placenta was histologically examined to diagnose chorioamnionitis.

 Ethical approval was obtained, and Data were analysed using Statistical Package for the Social Sciences (SPSS) version 23 with level of statistical significance set at P<0.05 and CI at 95%.

RESULTS

One hundred and twenty-two women were recruited for this study The mean age was 30.2 ±5.4 years with 82 (77.2%) in the 25-35 years’ age group. Ninety-one (74.6%) of the women presented with PROM at gestational age of 32 to 34 weeks. Seventy-three (59.3%) of the respondents had no constitutional symptoms. Majority (85, 69.7%) had spontaneous vaginal delivery.

Forty-eight (39%) of the fetuses had TTD less than 5^th Centile for their GA on ultrasound scan.

Fifty-seven (46.7%) of the women had placenta histological features of chorioamnionitis and there was a significant association between small thymus and histological chorioamnionitis (P < 0.001) compared with apparently normal thymus. The Sensitivity was increased with the number of thymic ultrasounds done before delivery.

CONCLUSION

 Fetal thymus ultrasound scanning seemed to be a promising sensitive predictor for the occurrence of choriomanionitis in women with preterm rupture of membranes.